Attempts to prepare first-row transition metal ion complexes of the system C-S-S-C, to characterize these complexes crystallographically and by various spectroscopic methods, and to explain the relationship between structure and chemical behavior are continuing. The polydentate disulfide ligands vary according to the number of coordinating sites, the order of the amines involved, the chelate ring sizes, and the aromaticity and steric bulk of the groups attached to the alpha-carbon of the disulfide groups. Complexes of Ni(II) and Cu(I) have been successfully prepared and described. An Mn(II) complex has been shown to be isostructural to a NI(II) complex in the crystal. It is hoped that Co(II) and Fe(II) complexes can be prepared. The saturated NCCSSCCN complex of Ni(II) has apparently been prepared. This same complex of Cu(I) is not stable. The Cu(I)-S bond length is much shorter than the Ni(II)-S length, after correcting for plausible ionic radii, indicating that an appreciable covalent backbonding interaction exists. Also, the disulfide bond is lengthened slightly by coordination to Cu(I), as compared to no modification noted upon Ni(II) coordination. These bond length changes correlate well with the S-S and C-S infrared stretch bands.